This section is intended to introduce the reader to various aspects of art, which may be associated with exemplary embodiments of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with information to facilitate a better understanding of particular techniques of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not necessarily as admissions of prior art.
The utilization of natural gas in the world energy market is growing faster than that of any other fossil fuel and is expected to continue to become increasingly important in the foreseeable future. Stranded natural gas reserves are expected to be a major supply source for the natural gas portion of the world energy market. Some sources estimate that stranded natural gas reserves account for about 50% of the total natural gas reserves held by the top 10 countries, and between 2,700 and 3,400 trillion cubic feet (tcf) worldwide. Stranded Natural Gas Reserves, Energy Business Daily, Sep. 27, 2007, found at http://energybusinessdaily.com/oil_gas/stranded-natural-gas-reserves/. As suggested by its name, these reserves are in remote or otherwise difficult to access areas. Utilizing and monetizing these stranded natural gas reserves is one of the world's toughest energy challenges.
Significant natural gas resources are located in regions of the world that are remote or otherwise stranded from gas markets and/or infrastructure (e.g., pipelines). Some methods currently considered to commercialize this remote or stranded gas are liquefaction (e.g., LNG), conversion to a liquid (e.g., syncrude or gas to liquid (GTL)), or compressed natural gas (CNG). Note that CNG is not currently in wide commercial use. Major challenges often limit the economic applicability of each of these methods: transportation energy efficiency, conversion energy efficiency, and economic efficiency. Additionally, environmental factors such as the release of green house gasses (GHG) should be considered in any proposed energy solution.
Overall transportation and conversion energy efficiency for liquefaction is reasonably high. The LNG process includes three major components: liquefaction (e.g. conversion), transportation, and re-vaporization/energy conversion (e.g. re-conversion). Combined, the total energy efficiency hovers from about 40% to 50% with the possibility of being over 60% in the near future with advances in the re-vaporization/energy conversion (re-conversion) efficiency. However, the economic efficiency of liquefaction suffers from the high cost of liquefaction plants, regasification terminals, cryogenic storage, and specialized carriers. Initial costs for such operations can easily exceed $2 billion and have high operational costs. As such, liquefaction is generally only a feasible economic option at relatively large quantities for transport over significant distances (over about 1,000 miles).
The economics of the GTL approach is about the same. Even though transportation costs for higher molecular weight liquids (e.g., syncrude, diesel) are lower than for LNG, a major challenge to convert gas to higher molecular weight liquids is overall energy conversion efficiency. Like the LNG process, the GTL process includes three major components: liquids conversion, transportation, and combustion (e.g. re-conversion). Combined, the total energy efficiency is from about 20% to about 30%. The economic efficiency is a little better than for LNG, but not enough to offset the lower energy conversion efficiency.
In some regions, flame stable remote natural gas is flared (burned in the atmosphere) rather than sequestered, sold or cleaned up. This is currently an economic, but wasteful approach to dealing with remote or stranded natural gas reserves. This natural gas may be gas associated with an oil production operation, or sour or acid gas that requires significant processing to be “saleable.” Flaring or releasing stranded natural gasses is currently the target of significant regulatory action, but many remediation options are expensive, reducing the economic incentive to treat the gas.
As such, a more energy efficient and economically efficient way to utilize or monetize remote or stranded natural gas resources is desired.
Other related material may be found in D. GSTOEHL, et al., A Quenching Apparatus for the Gaseous Products of the Solar Thermal Dissociation of ZnO, J. of Material Science, Accepted 27 Nov. 2007; ECONOMIDES, MICHAEL J. and MOKHATAB, SAEID, Compressed Natural Gas: Monetizing Stranded Gas, Energy Tribune, posted on Oct. 8, 2007, found at www.energytribune.com/articles.cfm?aid=643; COWAN, GRAHAM R. L., Boron: A Better Energy Carrier Than Hydrogen? Jun. 12, 2007, found at http://www.eagle.ca/˜gcowan/boron_blast.html.